HTTP Triggers

You can invoke Cloud Functions with an HTTP request using the POST,
PUT, GET, DELETE, and OPTIONS HTTP methods. To create an HTTP endpoint
for your function, specify --trigger-http as the trigger type when deploying
your function. From the caller's perspective, HTTP invocations are synchronous,
meaning that the result of the function execution will be returned in the
response to the HTTP request.
Note: Functions with HTTP(S) triggers are not supported in projects whose IDs
contain a colon.

For example, the following gcloud command deploys a function to the Node.js 8
runtime that will be triggered by HTTP requests: